Method and apparatus for making devices

ABSTRACT

A method and an apparatus for manufacturing a device are provided. The method and the apparatus can form micro wiring without undesired wetting and spreading using an inexpensive functional-liquid supplying method. A method for forming a device, such as a radiofrequency identification tag, includes: making patterns at a plurality of sections having different degrees of affinity to the functional liquid on a substrate to form the device; and supplying the functional liquid to the selected section having high affinity to the functional liquid. Forming the plurality of sections having different degrees of affinity to the functional liquid includes;, for example: supplying an organosiloxane film on the substrate, and exposing the organosiloxane film through an optical mask.

This is a Division of application Ser. No. 10/197,462 filed Jul. 18,2002. The entire disclosure of the prior application is herebyincorporated by reference herein in its entirety.

TECHNICAL FIELD

The present invention relates to methods and apparatuses for makingdevices. In particular, it relates to improvements on methods andapparatuses for making devices by forming a desired pattern on asubstrate by a functional-liquid supplier such as an inkjet dischargeror the like.

BACKGROUND ART

Circuit devices such as semiconductor devices and the like are made byforming circuit patterns or wiring patterns on substrates made ofmaterials such as silicon, glass, polyethylene terephthalate (PET), orpolyimide. Conventionally, these devices have been made by alithographic method, for example. In the lithographic method, aphotosensitive material called resist is supplied onto a substrate andis developed by irradiation on a circuit pattern. Metal ions are thenimplanted to form the circuit pattern. The lithographic method requireslarge-scale equipment and complicated steps. Therefore, themanufacturing cost is also high.

An example of a method for forming wiring patterns is an etching method.In this method, a metal foil is affixed to the surface of a substrate,and a resin resist is applied to perform patterning by photolithographyor the like and to remove the metal foil at the portions where theresist is removed. However, the etching method has a problem of highcosts. A method whereby the wiring pattern is supplied by printing hasbeen proposed, but the quality varied from one wiring pattern toanother, thus causing a quality unstability problem.

Another possible method for forming a wiring pattern is by discharging ametal-containing liquid instead of ink onto a substrate using an inkjetdischarging head. The resolution of the inkjet discharging head is high,e.g., 400 dpi; hence, a desired pattern having a width on the order ofmicrometers can be formed without equipment such as a semiconductorplant if a functional liquid can be discharged from individual nozzles(apertures).

DISCLOSURE OF INVENTION

However, when droplets discharged by the inkjet method land on thesurface of the substrate, the droplets excessively spread on the surfaceof the substrate, or the shape of the droplets remains as the outline ofthe wiring pattern, thereby forming irregularities of the substratesurface, which is a problem.

Moreover, no method or apparatus that can efficiently formthree-dimensional wirings, which connect each electric circuitspositioned on the different layers of the multiple-layers substrate, haspreviously been known.

The present invention aims to provide a method and apparatus for makinga device by which micro wiring can be formed using an inexpensivefunctional-liquid supplying method without undesirable wetting andspreading of the droplets.

It is another object of the present invention to provide a method and anapparatus for efficiently making a device having three-dimensionalwiring.

To achieve these objects, in the present invention, a method for makinga device by supplying a functional liquid onto a substrate for formingthe device, includes the steps of making patterns with the functionalliquid at a plurality of sections having different degrees of affinityto the functional liquid on the substrate for forming the device andsupplying the functional liquid to selected sections having highaffinity to the functional liquid among the plurality of the sections.

In the above manufacturing method, the substrate for forming the deviceis preferably a substrate for a radiofrequency identification tag, andthe functional liquid is preferably a metal containing liquid forforming an antenna of the radiofrequency identification tag.

In the above manufacturing method, the step of forming the plurality ofsections having different degrees of affinity to the functional liquidpreferably includes a substep of forming an organosiloxane film on thesubstrate and a substep of exposing the organosiloxane film through anoptical mask.

In the above manufacturing method, the step of forming the plurality ofsections having different degrees of affinity to the functional liquidpreferably includes a substep of forming a fluoroalkylsilane film on thesubstrate and a substep of exposing the fluoroalkylsilane film throughan optical mask.

In the present invention, another method for forming a device bysupplying a functional liquid on a substrate for forming the deviceincludes the steps of making patterns of banks for preventing overflowof the functional liquid on the substrate for forming the device andsupplying the functional liquid on selected areas inside the banks.

In the present invention, an apparatus for making a device by supplyinga functional liquid on a substrate for forming the device, includes apatterning unit for making patterns on a plurality of sections havingdifferent degrees of affinity to the functional liquid on the substratefor forming the device and a functional-liquid supplier for supplyingthe functional liquid to selected sections having high affinity to thefunctional liquid among the plurality of sections.

In the above device making apparatus, the substrate for forming thedevice is preferably a substrate for a radiofrequency identificationtag, and the functional liquid is preferably a liquid containing metalfor forming an antenna of the radiofrequency identification tag.

In the above device making apparatus, the patterning unit for formingthe plurality of sections having different degrees of affinity to thefunctional liquid preferably includes a photosensitive materialsupplying unit for supplying an organosiloxane film on the substrate andan exposing unit for exposing the organosiloxane film through an opticalmask.

In the above device making apparatus, the patterning unit for formingthe plurality of sections having different dgrees of affinity to thefunctional liquid preferably includes a photosensitive materialsupplying unit for supplying a fluoroalkylsilane film onto the substrateand an exposing unit for exposing the fluoroalkylsilane film through anoptical mask.

In the present invention, another apparatus for making a device bysupplying a functional liquid onto a substrate for forming the deviceincludes a patterning unit for making patterns of banks for preventingthe overflow of the functional liquid on the substrate for forming thedevice and a functional liquid supplying unit for supplying thefunctional liquid on selected areas inside the banks.

In the present invention, yet another method for making a device bysupplying a metal-containing liquid onto a substrate for forming thedevice includes the steps of forming a hole in the substrate for formingthe devices and supplying the metal-containing liquid into the hole.

In the above device making method, terminals of electrical circuitdevices are preferably disposed in the hole at different positions inthe substrate thickness direction.

Preferably, in the above device making method, the substrate has amultilayer structure comprising a plurality of electrical circuit layersand at least one insulating layer between the electrical circuit layers,and the metal-containing liquid in the hole electrically connectselectrical circuits of different layers to each other.

In the above device making method, the hole is preferably replaced witha plurality of slits extending in parallel to each other in a particulardirection in the substrate surface.

In the present invention, yet another apparatus for making a device bysupplying a metal-containing liquid to a substrate for forming thedevice includes a processing unit for forming a hole in the substratefor forming the device and a liquid supplying unit for supplying themetal-containing liquid into the hole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 includes (1) a plan view and (2) an auxiliary cross-sectionalview of an RFID tag made by a method according to an embodiment of thepresent invention.

FIG. 2 includes manufacturing step diagrams for describing the methodfor making the RFID tag,

FIG. 3 is a schematic perspective view of a speaker made by the methodof this embodiment.

FIG. 4 is a front perspective view of electrical wiring made on a wallby the device making method of this embodiment.

FIG. 5 includes cross-sectional views of a device havingthree-dimensional wiring according to manufacturing steps made by thedevice making method of this embodiment.

FIG. 6 includes (a) a plan view and (b) a cross-sectional view takenalong line B-B of an anisotropic conductive film 61 made by the devicemaking method of this embodiment.

FIG. 7 is a schematic perspective view of a device making apparatus usedin the above-described device making method.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will now be described withreference to the drawings.

<First Embodiment>

This embodiment is described the formation of an antennal for a radiofrequency identification (RFID) tag as an example.

(Mechanism of RFID tag)

An RFID tag is an electronic circuit used in a so-called radiofrequencyidentification system. This system is constituted from three parts: (1)a transponder (transmitter-receiver) called a “tag”; (2) a tag reader;and (3) a data processing system, such as a computer.

The tag reader includes an electronic device and an antenna, generatesradio waves for activating the tag, and receives a radio signal from thetag. The received data is checked and decoded by the electronic device.

The tag includes an IC and an antenna. The IC has a memory section thatstores an identification code and other data. The content of the memoryis transmitted via radio waves to the tag reader when the IC chip isoperated.

In most RFID systems, the tag reader emits radio waves to a particularzone that is determined by the frequency employed by the system and thesize of the antenna. When one tag passes through this zone, the tagdetects the radio waves from the tag reader and transmits the datastored in the tag.

The tag reader, after receiving the data from the tag, decodes the dataand determines whether the data is valid. If the data is valid, it istransmitted to the data processing system, such as a computer.

Tags are classified into two types: active types and passive types. Anactive tag operates by power from a battery either connected to the tagor installed inside. Active tags are advantageous since the power supplyfrom the tag reader can be decreased and the readable distance isgenerally long. A passive tag does not require an external power sourceand operates by the power obtained from the energy emitted from the tagreader. Passive tags are much lighter and smaller than active tags, areinexpensive, and have no substantial limit to their lifetime.

(Configuration of RFID tag)

FIG. 1 includes (1) a plan view and (2) an auxiliary cross-sectionalview of an RFID tag made by a method according to the embodiment of thepresent invention. As shown in FIG. 1(1), an RFID tag 10 includes an IC12 formed on a PET substrate 11, a spiral antenna 13 connected to theIC, a solder resist 14 formed on part of the antenna, and a Ag line 15formed on the solder resist. The Ag line 15 connects the ends of theantenna to each other so as to form a loop.

The antenna 13 is formed into a spiral on the substrate 11 with apredetermined gap between windings. Each winding of the spiral isarranged so as not to be short-circuited with the adjacent windings. Inorder to prevent short-circuiting of the windings, the metal for makingthe antenna must be accurately arranged at predetermined positions onthe substrate. In discharging a metal-containing liquid for forming theantenna onto the substrate by an inkjet method, the outline of theantenna must not have irregularities of the surface.

(Method for making RFID tag)

In this embodiment, plural sections having different degrees of affinityto the metal-containing liquid for making the antenna are formed withdesired patterns. Subsequently, the liquid is discharged by the inkjetmethod. The plural sections having different degrees of affinity arepreferably a combination of sections having high affinity and sectionshaving no affinity. To be more specific, a high-affinity section isprovided in the section where the antenna is to be formed, and ano-affinity section is provided in the section where no antenna is to beformed. In particular, when the metal-containing liquid for forming theantenna, e.g., a colloidal solution of Au, Ag, Cu, or the like, isaqueous, the section where the antenna is to be formed is hydrophilicand the section where no antenna is to be formed is hydrophobic. Whenthe metal-containing liquid is a hydrophobic organic solvent, thesection where the antenna is to be formed is oleophilic and the sectionwhere no antenna is to be formed is oleophobic.

FIGS. 2(1) to (4) are manufacturing step diagrams for explaining amethod for making the above-described RFID tag. An example of a methodfor forming patterns including sections having different degrees ofaffinity on the substrate is a method employing an organosiloxane. Forexample, an organosiloxane containing a titanium oxide (TiO₂)photocatalyst is applied on a polyimide substrate, as shown in FIG.2(1), by a spin-coating method or an inkjet method and is exposedthrough an optical mask to 254 nm ultraviolet light from a high-pressuremercury lamp. The exposed portion of the hydrophobic organosiloxanebecomes hydrophilic.

Subsequently, wiring is drawn with an Au colloidal solution, i.e.,“perfect gold” available from Vacuum Metallurgical Co., Ltd., by aninkjet method. The resulting wiring is baked in air at 250° C. for 30minutes so as to obtain a gold antenna wiring 13 shown in FIG. 2(2). Inmaking the RFID tag, an IC is mounted, as shown in FIG. 2(3), and thesolder resist 14 is applied by the inkjet method, as shown in FIG. 2(4).An Ag colloidal solution, i.e., “perfect silver” available from VacuumMetallurgical Co., Ltd., is applied by the inkjet method and is baked at250° C. for 30 minutes so as to form the Ag line 15 which connects theends of the antenna 13 to each other so as to form a loop. The RFID tag10 shown in FIG. 1 is thus manufactured.

It should be noted that it may be difficult to form an IC of the samesize as the IC 12 shown in the drawings by the inkjet method consideringthe resolution of present inkjet methods. However, a larger IC can bemanufactured by the inkjet method. By performing all of the steps by theinkjet method, the production efficiency and the cycle time can bedrastically improved. Moreover, inexpensive RFID tags can bemanufactured by improving the production efficiency and reducing themanufacturing cost, and disposable RFID tags may become a practicaloption.

In the above example, organosiloxane is applied on the entire surface ofthe substrate, and the section that needs to be hydrophilic is exposedto light. However, organosiloxane need not be applied on the entiresurface of the substrate. In particular, when the metal-containingliquid is discharged to the section where the antenna is to be formed byan inkjet method, it is sufficient to have the metal-containing liquidstay in the section where the antenna is to be formed and not in thesection where the antenna is not to be formed. Thus, while the sectionwhere the antenna is to be formed needs to be hydrophilic, only theborder area with the hydrophilic area in the section where the antennais not to be formed needs to be hydrophobic. Thus, within the sectionwhere the antenna is not to be formed, no organosiloxane needs to beapplied in the regions sufficiently distant from the border with thesection where the antenna is to be formed.

Another example of a method for making hydrophilic & hydrophobicpatterns on the substrate is a method using fluoroalkylsilane (FAS).Fluoroalkylsilane is a long molecule having a fluoroalkyl group and ahydrolysis group, e.g., halogen, ethoxy, methoxy, or the like, at thetwo ends. A siloxane bond is formed by the reaction of the hydrolysisgroup and the hydroxy group on the substrate, and, as a result, a filmexposing fluoroalkyl groups is formed on the surface of the substrate.This film is monomolecular in most cases, which is particularlypreferable because a monomolecular film has a uniform thickness and auniform liquid-repellent property over the entire surface. For example,perfluorodecyl-1,1,2,2-tetrahydro-decyl-triethoxysilnae (FAS 17) and thesubstrate are placed in a hermetically sealed container and heated at120° C. for 2 hours to form a liquid-repellent monomolecular film. Thisfluoroalkylsilane film becomes hydrophilic by the radiation of UV light.More preferably, a suitable photocatalyst is used.

The material for forming the antenna wiring 13 or the like is notlimited to the above described material. For example, a Cu-SOM liquidavailable from Vacuum Metallurgical Co., Ltd., a nano-paste from HarimaChemicals, Inc., or the like may be used. The former is suitable forforming copper wiring. The latter can form micro metal wiring bylow-temperature baking at approximately 150° C. to 200° C. The materialis not limited to metal; a conductive polymer such aspolyethylene-dioxythiophene (PEDT) may be used. In such a case, sectionshaving different degrees of affinity to the conductive polymer arepatterned, and the melted conductive polymer is applied onto thehydrophilic sections.

Another method for making patterns on the substrate so as to fix thefunctional liquid at predetermined positions of the substrate is to formbanks that prevent overflowing of the functional liquid on thesubstrate. By this method, the thickness of the device must be increasedby the thickness of the banks. Accordingly, a planarization process isrequired after discharging and baking the functional liquid. However,the method is suitable when making a thick wiring is desired.

<Second Embodiment>

A micro lens array (MLA) has many rows of micro lenses arranged on asubstrate and are used in liquid crystal display panels, projectors,scanners, or the like. In forming a micro lens array, a method ofdischarging a lens material, i.e., a transparent epoxy resin or thelike, onto a substrate by an inkjet method may be employed. The shape ofeach lens and the rows of the lenses can be precisely formed byprocessing the sections of the substrate where lenses are to be formedto have affinity to this resin while processing the sections of thesubstrate where no lenses are to be formed to be repellent to thisresin.

The method for applying the functional liquid is not limited to theinkjet method; a method that uses a dispenser can also be employed.

The substrate on which the device of this embodiment is formed is notlimited to PET, glass, or silicon substrates. The device may be formedon a sheet of paper, for example, so as to detach the device from thepaper and attach it on a different substrate.

According to the manufacturing method of this embodiment, the functionalliquid can be selectively applied only to the regions where thefunctional liquid is necessary. Thus, compared to the case where thefunctional liquid is applied over the entire surface, the material canbe efficiently used and the cost can be reduced.

<Third Embodiment>

FIG. 3 is a schematic perspective view of a speaker made by amanufacturing method of this embodiment. As shown in FIG. 3, a liquid inwhich fine metal particles are dispersed is discharged on a vibratingplate 31 to form a coil 32. The vibrating plate 31 is arranged to opposea magnetic flux generating unit 33 such as a magnet. An analog signal isgenerated and a signal current is supplied to the coil 32 on thevibrating plate 31 from an amplifying circuit 34 so that a magnetic fluxis generated from the coil 32 and sound is produced by the vibration ofthe vibrating plate 31 resulting from the interaction between the coiland the magnetic flux generating unit 33. The vibrating plate 31 may beplanar or may be of a cone type. The face of the vibrating plate 31 onwhich the coil is formed may be covered with a waterproof film or thelike to form a thin, waterproof speaker.

<Fourth Embodiment>

FIG. 4 is a front perspective view of electrical wiring formed on a wallby a method for manufacturing a device according to this embodiment. Ona residential wall unit 41, a power terminal 42, a phone terminal 44, acable TV terminal 46, and the like are installed. The power terminal 42is connected to a wire 43, the phone terminal is connected to a signalline 47, and the TV terminal is connected to a signal line 45, so thatpower and signals can be output. A wall-hanging TV 48 may be installedon the wall unit 41, and the wire 43 and the signal line 47 may beconnected to this wall-hanging TV 48 so that broadcast signals can bereceived and images and sound can be output without exposed componentssuch as electrical cables or the like.

The wire 43 and the signals lines 45 and 47 can be formed by applying aliquid in which fine metal particles are dispersed onto predeterminedpositions of the wall unit by the inkjet method and by drying andhardening the applied liquid.

<Fifth Embodiment>

FIG. 5 includes cross-sectional views of a device havingthree-dimensional wiring made according to a device manufacturing methodof this embodiment. An insulating substrate 51, which is the same asthat in the first embodiment is subjected to a required surfacetreatment (S1), and electrical circuits 52 are formed on the substrate(S2). Here, two layers of electrical circuits 52 are formed by applyinga liquid in which fine metal particles are dispersed onto both surfacesof the substrate by the inkjet method according to predeterminedpatterns, and by drying and hardening the liquid. The method for formingthe electrical circuits 52 is not limited to this. Alternatively, aninsulating layer may be formed on an electrical circuit, and anotherelectrical circuit may be formed on the insulating layer.

Next, a hole 53 is formed (S3) in the substrate. The hole 53 is toelectrically connect the electrical circuits 52 to each other. Terminalsof the electrical circuits 52 are exposed at the wall of the hole 53 atdifferent positions in the substrate thickness direction. The hole 53may penetrate both surfaces of the substrate or may penetrate only oneof the surfaces. The hole 53 may be made by, for example, applying aphotosensitive material according to a predetermined pattern anddeveloping the material by exposure, or by etching with a mask having apredetermined pattern. The diameter of the hole 53 is, for example, 100μm.

Next, a metal-containing liquid 54 is fed into the hole 53 by the inkjetmethod (S4). The wall of the hole 53 is preferably processed in advanceto exhibit affinity to the liquid according to the property of themetal-containing liquid. The electrical circuits 52 can be connected toeach other and three-dimensional wiring can be formed by drying andhardening the liquid 54 fed therein. Since a connection between theselayers needs to be formed, after hardening, the hole 53 may becompletely filled with metal or, alternatively, a metal film 55 may beformed only on the wall of the hole 53 (S5).

<Sixth Embodiment>

FIG. 6 includes (a) a plan view and (b) a cross-sectional view, takenalong line B-B, of an anisotropic conductive film 61 made by a devicemanufacturing method of this embodiment. Slits 62 extending in apredetermined direction are formed in parallel on the surface of a filmsuch as a silicon rubber film, a polyester film, or the like. After anappropriate surface treatment, a liquid in which fine metal particlesare dispersed is discharged into the slits 62 by the inkjet method. Theliquid is dried and hardened to form an anisotropic conductive film 61which is electrically conductive in a particular direction of the filmsurface and insulative in a direction perpendicular to this particulardirection. The slits 62 may penetrate the substrate in the filmthickness direction, as shown in FIG. 6(b), or may be formed as groovesthat do not penetrate the substrate.

<Manufacturing apparatus>

FIG. 7 is a schematic perspective view of an apparatus for manufacturinga device used in the above described manufacturing methods. A devicemanufacturing apparatus 100 includes an inkjet-type functional-liquidsupplier and has an inkjet head group 1, an X-direction driving shaft 4,a Y-direction guiding shaft 5, a controller 6, a table 7, a cleaningmechanism 8, and a base 9.

The inkjet head group 1 has inkjet heads for supplying a particularfunctional liquid, e.g., a metal-containing liquid or a photosensitivematerial, onto a substrate by discharging the functional liquid fromnozzles (apertures).

A substrate 101 of PET, glass, silicon, paper, or the like, onto whichthe functional liquid is supplied by the functional-liquid supplier isplaced on the table 7. The table 7 has a mechanism for fixing thedischarge medium at a reference position.

An X-direction driving motor 2 is connected to the X-direction drivingshaft 4. The X-direction driving motor 2 is a stepping motor or the likeand rotates the X-direction driving shaft 4 upon receiving anX-direction driving signal from the controller 6. When the X-directionrotating shaft 4 is rotated, the inkjet head group 1 moves in the X-axisdirection.

The Y-direction guiding shaft 5 is fixed on the base 9. The table 7 hasa Y-direction driving motor 3. The Y-direction driving motor 3 is astepping motor or the like and moves the table 7 in the Y-axis directionupon receiving a Y-direction driving signal from the controller 6.

The controller 6 supplies a voltage for controlling discharge ofdroplets to each head in the inkjet head group 1. The controller 6 alsosupplies a driving pulse signal for controlling the movement of theinkjet head group 1 in the X-axis direction to the X-direction drivingmotor 2 and another driving pulse signal for controlling the movement ofthe table 7 in the Y-axis direction to the Y-direction driving motor 3.

The cleaning mechanism 8 includes a mechanism for cleaning the inkjethead group 1. The cleaning mechanism 8 includes a Y-direction drivingmotor (not shown). The Y-direction driving motor moves the cleaningmechanism 8 along the Y-direction guiding shaft 5. The movement of thecleaning mechanism 8 is also controlled by the controller 6.

Note that although no exposing apparatus for making hydrophilic &hydrophobic patterns is shown in FIG. 7, a known exposing apparatus suchas that using a mercury lamp can be used in the manufacturing method ofthis embodiment.

INDUSTRIAL APPLICABILITY

According to the present invention, a method and a device manufacturingapparatus which can form micro wiring by a low-cost functional-liquidsupplying method without undesired wetting and spreading of the dropletscan be provided. Moreover, a method and an apparatus for efficientlymaking a device having three-dimensional wiring can be provided.

1. A method for forming a device by supplying a functional liquid on asubstrate to form the device, comprising: making patterns of banks toprevent overflow of the functional liquid on the substrate to form thedevice; and supplying the functional liquid on selected areas inside thebanks.
 2. An apparatus for making a device by supplying a functionalliquid onto a substrate to form the device, comprising: a patterningunit to make patterns of banks to prevent the overflow of the functionalliquid on the substrate to form the device; and a functional liquidsupplying unit to supply the functional liquid on selected areas insidethe banks.
 3. A method for making a device by supplying ametal-containing liquid onto a substrate to form the device, comprising:forming a hole in the substrate to form the device; and supplying themetal-containing liquid into the hole.
 4. The method for making thedevice according to claim 3, further including disposing terminals ofelectrical circuit device patterns in the hole at different positions inthe substrate thickness direction.
 5. The method for making the deviceaccording to claim 4, the substrate having a multilayer structureincluding: a plurality of electrical circuit pattern layers and at leastone insulating layer between the electrical circuit layers, and themetal-containing liquid in the hole electrically connecting electricalcircuit patterns of different layers to each other.
 6. The method formaking the device according to claim 3, further including replacing thehole with a plurality of slits extending in parallel to each other in aparticular direction in the substrate surface.
 7. An apparatus formaking a device by supplying a metal-containing liquid to a substrate toform the device, comprising: a processing unit to form a hole in thesubstrate to form the device; and a liquid supplying unit to supply themetal-containing liquid into the hole.